神经肌肉电刺激治疗脑卒中后吞咽障碍疗效观察

目的观察神经肌肉电刺激（Neuromuscular electrical stimulation,NMES）治疗脑卒中后吞咽障碍（Dysphagia after stroke,DAS）的疗效。方法将经电视透视吞咽检查（Videofluoroscophic swallowing study,VFSS）确诊的60倒DAS患者随机分为两组,治疗组30例,对照组30倒。两组均给予常规内科治疗及传统康复治疗,治疗组同时给予NMES治疗,疗程为10d。比较两组治疗前、治疗10d的VFSS评分及治疗10d、治疗后1个月、治疗后6个月的疗效。结果治疗前两组VFSS评分比较无统计学意义（P〉0．05）;治疗10d,治疗组VFSS评分明显高于对照组,有效率、显效率高于对照组,差异有统计学意义（P〈0．05）,治疗后1个月,两组有效率无统计学意义（P〉0．05）,但治疗组显效率明显高于对照组（P〈0．05）;治疗后6个月,两组吞咽障碍预后良好率无差异（P〉0．05）。结论NMES治疗DAS的近期疗效肯定,疗效可持续1个月。     

A novel modulation strategy to increase stimulation duration in neuromuscular electrical stimulation

Introduction: Neuromuscular electrical stimulation (NMES) has been shown to be an effective treatment for muscular dysfunction. Yet, a fundamental barrier to NMES treatments is the rapid onset of muscle fatigue. The purpose of this study is to examine the effect of feedback‐based frequency modulation on the closed‐loop performance of the quadriceps during repeated dynamic contractions. Methods: In the first experiment, subjects completed four different frequency modulation NMES protocols utilizing the same amplitude modulation control to compare the successful run times (SRTs). A second experiment was performed to determine the change in muscle response to high‐ and low‐frequency stimulation. Results: Compared with constant‐frequency stimulation, results indicate that using an error‐driven strategy to vary the stimulation frequency during amplitude modulation increases the number of successful contractions during non‐isometric conditions. Conclusion: Simultaneous frequency and amplitude modulation increases the SRT during closed‐loop NMES control. Muscle Nerve 44: 382–387, 2011     

模型动物失神经支配及神经肌肉电刺激的可编程植入式神经肌肉电刺激器

背景：植入式神经肌肉电刺激器可用于研究功能性电刺激对动物失神经肌肉的作用机制,但体积偏大,功能单一。目的：设计一种微型、参数可调的植入式神经肌肉电刺激器。方法：基于红外通信技术,以MSP430为控制核心,采用低功耗设计,经体外控制器设置参数,产生电荷平衡的双相脉冲序列,可对神经或肌肉进行电刺激。结果与结论：实验设计的刺激器可在体编程,能够灵活设置刺激电压幅值、频率、脉宽和间隔时间等参数。多参数的设置丰富了刺激协议选择性,可最小化对目标神经肌肉临近组织的不可预测刺激,优化了功耗设计,可确保实验动物的安全性。     

神经肌肉电刺激结合饮食指导对卒中后吞咽障碍患者的疗效

目的 探究神经肌肉电刺激结合饮食指导对脑卒中后吞咽障碍的治疗,并分析其治疗效 果。方法 选择2014 年6 月—2016 年10 月因脑卒中后首次出现吞咽障碍患者95 例纳入本次研究,并 随机分为研究组（47 例）和对照组（48 例);后因肺部感染等病因出现脱落,研究组脱落2 例,对照组脱落 3 例。对照组采用传统吞咽康复训练,研究组患者则在进行传统吞咽康复训练基础上,根据吞咽障碍发 生原因,进行神经肌肉电刺激治疗,并结合相应的饮食指导,包括改进食物性状、调整患者进食体位、 针对性改进喂养方法、选择进食器具、训练吞咽技巧等方面进行全面指导。为评估治疗效果,对脑卒 中吞咽障碍患者于治疗前后分别采用电视荧光放射吞咽功能检查（VFSS）评分法、功能性经口摄食量表 （FOIS）、视频吞咽造影功能障碍量表（VDS）评价患者吞咽功能。结果 训练后两组的吞咽功能评分较训 练前均有显著提高（P＜ 0.05）,但训练后研究组功能评分明显高于对照组（P＜ 0.05）,研究组的好转情况 要显著优于对照组。两组患者干预前,摄食情况、VDS 评分比较,差异无统计学意义（P＞ 0.05）;干预后, 两组患者摄食情况、VDS评分均存在一定程度改善,且研究组优于对照组（P＜ 0.05）。研究组治疗总有 效率为86.67%,对照组为68.90%,研究组高于对照组（χ2=3.38,P=0.026）。结论 神经肌肉电刺激结合 饮食指导训练对改善脑卒中患者吞咽功能障碍的疗效优于单纯吞咽训练。     

Profile of neuropsychological deficits in older stroke survivors without dementia

BACKGROUND: Few studies have examined the profile of cognitive impairments in older stroke patients without dementia. METHOD: A standardized evaluation including a detailed neuropsychological assessment [Cambridge Examination for Mental Disorders in the Elderly--cognitive subscale (CAMCOG)] and computerised tests of attention and working memory from the Cognitive Drug Research battery were undertaken in 150 stroke survivors of >75 years of age and 30 elderly controls. RESULTS: The stroke survivors without dementia had significantly greater overall impairment on the CAMCOG, as well as significantly greater impairment in memory, simple reaction time, choice reaction time (CRT), vigilance accuracy, CRT variability, spatial working memory reaction time (SWMRT) and numerical working memory than the elderly controls (e.g. CRT [up] 33%, SWMRT [up] 61%, memory [down] 11%). CONCLUSION: Impairments of cognitive processing speed, working memory and executive functions are frequent in elderly stroke patients without dementia and represent the main cognitive components of early cognitive impairments.     

Turning off the central contribution to contractions evoked by neuromuscular electrical stimulation

Neuromuscular electrical stimulation can generate contractions through both peripheral and central mechanisms. The peripheral mechanism involves the direct activation of motor axons, while the central mechanism involves the activation of sensory axons that recruit spinal neurons through a reflex pathway. For use in functional electrical stimulation. One must have control over turning the central mechanism on and off. We investigated whether inhibition developed through antagonist muscle (tibialis anterior, TA) contractions elicited by electrical stimulation or by volition can turn off the central mechanism in triceps surae. Both electrical stimulation and voluntary contractions of TA reduced or eliminated plantar flexion torque produced by the central mechanism, indicating that inhibition induced via these contractions can effectively turn off the central contribution to force. These findings suggest that patterns of electrical stimulation may be able to generate periodic muscle contractions by turning the central contribution to muscular contractions on and off.     

国内电刺激治疗脑卒中后吞咽障碍的研究状况分析

背景：脑卒中后吞咽障碍在临床较为常见,电刺激是治疗脑卒中后吞咽障碍的新方法。目的：通过与国外研究相比较,了解国内关于电刺激治疗脑卒中后吞咽障的研究状况。方法：运用计算机在中国期刊全文数据库、万方数字化期刊全文库和维普数据库进行文献检索,采用关键词检索或主题词检索,检索词为“脑卒中/脑血管意外、吞咽障碍、电刺激”,以AND连接。检索时间段1989-01/2010-04。结果与结论：通过对上述3个数据库的文献检索,共搜索到符合标准的文献47篇,最早的文献发表于2003-03。通过对文献的分析,发现国内在电刺激治疗脑卒中后吞咽障碍的文献比重少,研究的质量不高,涉及面也很小,主要围绕临床运用疗效进行,与国际上的研究差距较大。因此在未来需要更多具有高质量、多角度的研究来探讨电刺激治疗脑卒中后吞咽障碍存在的问题。     

The effects of wide pulse neuromuscular electrical stimulation on elbow flexion torque in individuals with chronic hemiparetic stroke

Objective

Neuromuscular electrical stimulation that incorporates wide pulse widths (1 ms) and high frequencies (100 Hz; wide pulse-NMES (WP-NMES)) augments contractions through an increased reflexive recruitment of motoneurons in individuals without neurological impairments and those with spinal cord injury. The current study was designed to investigate whether WP-NMES also augments contractions after stroke. We hypothesized that WP-NMES would generate larger contractions in the paretic arm compared to the non-paretic arm due to increased reflex excitability for paretic muscles after stroke.

Methods

The biceps brachii muscles were stimulated bilaterally in 10 individuals with chronic hemiparetic stroke. Four stimulation patterns were delivered to explore the effects of pulse width and frequency on contraction amplitude: 20–100–20 Hz (4 s each phase, 1 ms pulse width); 20–100–20 Hz (4 s each phase, 0.1 ms); 20 Hz for 12 s (1 ms); and 100 Hz for 12 s (1 ms). Elbow flexion torque and electromyography were recorded.

Results

Stimulation that incorporated 1 ms pulses evoked more torque in the paretic arm than the non-paretic arm. When 0.1 ms pulses were used there was no difference in torque between arms. For both arms, torque declined significantly during the constant frequency 100 Hz stimulation and did not change during the constant frequency 20 Hz stimulation.

Conclusions

The larger contractions generated by WP-NMES are likely due to increased reflexive recruitment of motoneurons, resulting from increased reflex excitability on the paretic side.

Significance

NMES that elicits larger contractions may allow for development of more effective stroke rehabilitation paradigms and functional neural prostheses.     

Interleaved neuromuscular electrical stimulation: Motor unit recruitment overlap

Introduction: In this study, we quantified the “overlap” between motor units recruited by single pulses of neuromuscular electrical stimulation (NMES) delivered over the tibialis anterior muscle (mNMES) and the common peroneal nerve (nNMES). We then quantified the torque produced when pulses were alternated between the mNMES and nNMES sites at 40 Hz (“interleaved” NMES; iNMES). Methods: Overlap was assessed by comparing torque produced by twitches evoked by mNMES, nNMES, and both delivered together, over a range of stimulus intensities. Trains of iNMES were delivered at the intensity that produced the lowest overlap. Results: Overlap was lowest (5%) when twitches evoked by both mNMES and nNMES produced 10% peak twitch torque. iNMES delivered at this intensity generated 25% of maximal voluntary dorsiflexion torque (11 Nm). Discussion: Low intensity iNMES leads to low overlap and produces torque that is functionally relevant to evoke dorsiflexion during walking. Muscle Nerve 55 : 490–499, 2017     

Chronic stroke motor recovery: duration of active neuromuscular stimulation

Active neuromuscular stimulation is an effective behavioral intervention for motor recovery improvements after a stroke. However, the most effective active neuromuscular stimulation durations have not been determined. The present experiment investigated active stimulation durations (0, 5, and 10 s) coupled with bilateral movements on progress toward motor recovery in wrist and finger extension. Twenty-six stroke survivors with chronic hemiparesis were randomly assigned to the stimulation duration groups, and subjects completed 4 days of rehabilitation training over a 2-week period. Mixed design analyses of variance on the Box and Block scores, chronometric reaction times, and force modulation of the sustained muscle contraction task revealed distinct motor recovery improvements for both the 5 and 10 s stimulation duration groups in comparison to the 0 s duration control group. Further, the number of blocks moved by the 10-s duration group exceeded those moved by the 5-s duration group. In conclusion, the 5 and 10 s duration active stimulation/bilateral movement groups decreased residual motor dysfunctions that persisted beyond 12 months post stroke.     

Response of brainstem trigeminal neurons to electrical stimulation of the dura

The extracellular response of medullary trigeminal neurons to electrical stimulation of the dura was studied in anesthetized cats. Fifty-six medullary trigeminal units were excited by stimulation sites near major dural vessels with an average latency of 11.0 ms. Many units also responded to infraorbital nerve shock and had cutaneous receptive fields that included the ipsilateral periorbital region. These cutaneous responses were either wide dynamic range or nociceptive specific in type. Electrical stimulation of the midbrain periaqueductal gray region suppressed the response of medullary trigeminal units to either dural stimulation or infraorbital nerve shock. Medullary trigeminal neurons that receive convergent inputs from dura and facial skin may provide a physiological substrate for the cutaneous referral of dural sensation.     

Changes in neuromuscular function after training by functional electrical stimulation

We examined whether the neuromuscular function of rectus femoris (RF) and flexor digitorum brevis (FDB) in humans was modified after a 6-week training period of functional electrical stimulation (FES), and whether any effects persisted at the end of a 6-week post-FES recovery period. In both the stimulated and contralateral nonstimulated muscles, we recorded the muscle force, surface electromyogram, and M wave, and also measured the root mean square (RMS) and the median frequency (MF) during static contraction sustained until exhaustion at 60% of maximal voluntary contraction (MVC). FES was performed with symmetric biphasic pulses, with a ramp modulation of both the stimulation frequency and pulse duration. No changes in MCV and endurance time to exhaustion occurred in nonstimulated muscles, whereas a significant MVC increase occurred immediately after FES in RF (+14 +/- 5%) and FDB (+13 +/- 5%), these effects persisting 6 weeks after the end of FES. In FDB, FES also elicited a significant increase in endurance time to exhaustion (+18 +/- 7%). The M-wave characteristics never varied after FES, but a marked attenuation occurred in the MF decrease and the RMS increase measured at endurance time to sustained 60% MVC, especially in FDB, which contains the higher proportion of type II fibers. These data indicate that FES improves muscle function and elicits changes in central muscle activation. The benefits of FES were greater in FDB, which is highly fatigable, and persisted for at least a 6-week period.     

Effect of neuromuscular electrical stimulation frequency on muscles of the tongue

Introduction: Neuromuscular electrical stimulation (NMES) for the treatment of swallowing disorders is delivered at a variety of stimulation frequencies. We examined the effects of stimulation frequency on tongue muscle plasticity in an aging rat model. Methods: Eighty‐six young, middle‐aged, and old rats were assigned to either bilateral hypoglossal nerve stimulation at 10 or 100 Hz (5 days/week, 8 weeks), sham, or no‐implantation conditions. Muscle contractile properties and myosin heavy chain (MyHC) composition were determined for hyoglossus (HG) and styloglossus (SG) muscles. Results: Eight weeks of 100‐Hz stimulation resulted in the greatest changes in muscle contractile function with significantly longer contraction and half‐decay times, the greatest reduction in fatigue, and a transition toward slowly contracting, fatigue‐resistant MyHC isoforms. Discussion: NMES at 100‐Hz induced considerable changes in contractile and phenotypic profiles of HG and SG muscles, suggesting higher frequency NMES may yield a greater therapeutic effect. Muscle Nerve, 2018